1. Field of the Invention
The present invention relates to an electric spindle motor and a storage disk drive apparatus provided with the same.
2. Description of the Related Art
Conventionally, a storage disk drive apparatus, such as a hard disk drive or the like, includes a spindle motor for rotating a storage disk. In recent years, a fluid dynamic pressure bearing mechanism that makes use of the dynamic pressure of a lubricant held in a bearing gap between a rotor unit and a stator unit is used as a bearing mechanism in the spindle motor.
With the fluid dynamic pressure bearing mechanism, a tapering portion in which the width of the bearing gap increases toward the outside is formed near the opening of the bearing gap bordering the outside. The boundary surface of a lubricant is positioned in the tapering portion. Due to the capillary phenomenon and surface tension, the boundary surface of the lubricant is formed into a meniscus shape, which assists in preventing leakage of the lubricant.
When manufacturing this type of fluid dynamic pressure bearing mechanism, it is necessary to perform a cleaning step in which lubricant droplets adhering to the outer wall surface of the tapering portion are removed with a solvent or the like after the lubricant has been filled. Therefore, a limit has existed in shortening the manufacturing process.